I would think connecting to the main line in the street would have to be done by an approved plumber? It's method can widely vary depending on the original methods in the area. Also most towns will not take too kindly to a private residence deciding on there own to tear up the street and start hooking up to the mains.
I help a friend run his new sewer line. We dug the trench close to the street. Then rodded out the remaining section of clay tile. After we measured the approximate distance to the sewer line (looking at the man hole covers) and inserted PVC piping inside the clay tile. We sealed up the opening left around the pipe with cement. Then hooked the PVC to the house. This was done over 8 years ago and he hasn't had ANY problems with his drains since. and we avoided the costly expense of ripping up an repairing the street.
I would rather not see any angles more the 30 degrees, however the original line at my home was ran with TWO 90 degree bends within 15 feet of one another! That part hasn't really shown to be an issue. I wouldn't have ran it that way myself.